This invention generally relates to magnetically levitated vehicles, and more specifically, to generating power on such vehicles.
In a magnetically levitated vehicle, a group of magnets located on the vehicle are used to hold the vehicle in a levitated or suspended position and to propel the vehicle along a guideway. More specifically, a series of coils, referred to as traction coils or rail coils, are installed along the length of the guideway, and an alternating current, typically a three phase alternating current, is conducted through those coils. This current generates an electromagnetic field that moves along the guideway, and this field interacts with the magnetic field of the magnets on the vehicle to propel the vehicle along the guideway.
The magnets on the levitated vehicle are electromagnets which generate the primary magnetic fields. Recently, attention has been directed toward using superconducting wire for the vehicle electromagnets which produce the primary magnetic field for vehicle levitation and propulsion.
Power, of course, is needed on a magnetically levitated vehicle. For instance, if the vehicle employs an electromagnetic to generate the primary magnetic field, power is needed to produce the current that is conducted through the electromagnetic. In case the electromagnetic is a superconducting electromagnet, power is also needed to operate the refrigeration equipment associated with the superconducting materials. In addition, power is needed to supply other loads on the vehicle, such as heating, air conditioning, and lighting systems.
A typical 100 passenger magnetically levitated vehicle requires, for example, 150 kilowatts of power under all operating conditions. Storage batteries may be used to provide the power needed by a magnetically levitated vehicle; however, storage batteries add additional weight to the vehicle and, thus, increase the amount of power needed to levitate the vehicle.